Lift bridge



PQ JOOSTING;

LIFT BRIDGE. I APPLICATION FILED MAR. 7. 1921.

Patented July 11, 1922.,

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Patezated July H, 192.2,

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t te-5r I-IETER JOOSTING, 0F UTRECHT, NETHERLANDS.

LET BRIDGE.

Application filed March 7,

ed to be raised and lowered by means of ropes or the like operated by one or more stationary drums, and has for its object to provide simple means for moving the span, a further object being means for preventing the movable span from going out of square with its guide towers or columns. Still another object of the invention and one which results from the said improved means is lightness and simplicity in the structure of both movable span and fixed parts.

It has been proposed to mount the span hoisting and/or lowering machinery on the moving lifting span itself, but this system, which has been disclosed in U. S. specification for Patent No. 932,359, has the disadvantage that the weight of the lifting span is considerably increased. Other disadvans tageous features are that transmission of electric energy to the machinery on the span necessitates a trolley system, that telephonic communication between the movable engine room and the bank of the river or canal,

which is often unavoidable, is difficult to realize, that the bridgetender cannot overlook the ship way sufficiently from the lifted span and,in railway bridges, that the operation of the safety signalling system on the line by the bridge-tender requires complicated arrangements.

In other known systems the towers are at their tops interconnected by means of a fixed specification of Letters Patent.

Patented July 11, 1922,

1921. Serial No. 450,165.

at the other end of the span, and thence to a fixed-point at the top of the opposite column to which it is secured.

In case the span is counterbalanced by welghts in the usual way one or more lowering ropes or the like are to be used, each passing from the stationary drum over a sheave at the foot or in the lower part of the adjacent column, thence over a sheave at one end of the span, thence over a sheave 'at the other end of the span, and thence to a fixed point at the foot or in the lower part of the opposite column to which it is secured.

Owing to differences in the effect of friction in the sheaves at both ends of the span the latter might run out of square when belng raised or lowered. Therefore I may use guide rollers engaging vertical rails on the columns to keep the span in a horizontal position.

I prefer, however, to use instead of guide rollers two guide ropes, or two sets of guide ropes or the like, the one running approximately in the form of a Z from a fixed point at the top of one column over sheaves of the span to a fixed point at the foot of the other column, the other rope or set extending oppositely from the top of the other column over sheaves of the span to a fixed point at the foot of the first named column, in such a manner that the ropes or the like in-the form of a Z coact to ensure parallelism of the movement of the span.

The invention may be fully understood from the accompanying drawing which diagrammatically shows a lift bridge and the raising and lowering device therefore.

Figure 1 is a side elevation of the bridge showing the span lowered in full lines and elevated in dotted lines.

Figures 2 to 5 are diagrams of means for moving and guiding the span.

Figures 6 to 8 are diagrams of other means for preventing the lifting span from going out of square with the towers.

The counterbalanced span 6 is adapted to be lifted between the fixed, columns 7 and 8, the first of which is provided with the house 9 containing the lifting and lowering machinery. This house may, of course, also a sheave 14 in the span, a number of sustain ing rollers 15 in the span 6, a sheave '16 in the span and is secured to av fixed point17 near the top of thecolumn 8. i

The lowering rope orset of ropes 20 are shown in Figure 3.|Fr0m the lowering drum 19, which may ,bc'fixedonthesame shaft as the lifting drum 11, 0r' maybe combined with the latter, the rope 20 passes overasheave 21at the foot ofthe column 7, thence over a sheave22 at one end of'the span 6, overa number of supporting rollers 15*, a sheave 23,,at the, other end of the span to a fixed'point 24Iat the foot of the tower 8; g

Fig. 4 shows one of the guide ropes or sets of guide ropes 25 extending in the form of a 2. from a fixed point 26 near the top of column 7zover sheaves 27 and 28 and a number of supporting rollers 15 in the span I I the span to 'afixed to a fixed point 29 at the. foot of tower 8.

v A similar guide rope 30.is.shown in Fig. 5. It extends from a fixed point 31 near the top of the column 8 over sheaves 32 and- 33 anda number of sustainingrollers 15 in point St at the foot of tower 7.

All ropes may be provided withsuitable turn-buckles or spannerspermitting to eliminate slack therein .andtoy adjust the span so that the latter will be square with the yertical sides of the columns. k The guiding mechanism as diagrammatically shown in Figures 4 and 5 may be replaced by any other suitable or approved means. Figure 6 shows the lifting span 6 provided near each of its four corners with a set of two anti-friction rollers 35 and 36 suitably spaced'apart vertically, each set engaging a vertical rail: 37 secured to the towers According to Figure'Z, the lifting span is provided at each end with a horizontal shaft 38 at right angles to the longitudinal axis of the span and supported insuitable bearings, said shaft carryingtwo gears 39 meshing with vertical racks 40 on the towers. The shafts 38 at both ends'are coupled by mitre gearing so as to always rotate at equal angular speeds but inopposite directions.

I, Figure 8 shows the-span 6 as having a horizontal drum 11 at each end, ropes- 12 running. over each of these drums being fixed'at top'and f oot ofr-the adjacent tower, both drums .being coupled by, mitre gearing so as to always revolve at equal angular speeds,

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is 1. In a lift bridge, the combination with stationary. towers, of 'a span adapted for vertical travel between said towers, afixed lifting and lowering machinery, flexible pulling. means extending from said machinery over guiding means at the upper part of the tower adjacent to said machinery and thence over guides in the span .to a fixed 11 point iii the-upper part of the-other tower, and means adapted, to prevent the span from going out of square with the towers.

2. In a lift bridge,-thecombination with stationary towers, of a counterbalanced span adapted for vertical travel between said towers a fixed lifting and lowering machinery, flexible pulling means extending from said machinery over guidingmeans at the upper part of the tower adjacent to said machinery and over'guides inthe span to a fixed point in the upper part of the other tower, another flexible pulling means extending from saidmachinery over guiding means at the foot of the tower/adjacent to said machinery and thence over guides in the. span toa fixed point at the foot of the other tower, and means adapted to prevent the span from going out of square with thetowers. A

3. In a lift bridge, the combination with stationary towers, ofaspan adaptedfor vertical travel between said towers, a fixed lifting and lowering machinery, flexible pulling means extending from saidv machinery over guiding means at the'upper part of the tower-adjacent to said machinery and over guides in'the span ,to a fixed point in the upper part of the, other tower, and Z-shaped flexible pulling means of which the one extends-from a fixed pointat the top of one tower over guides in the span to a fixed point at the foot of the other tower and the other extends from a fixed point at the top of the other tower over guides in the span to a fixed point at the foot of the first mentioned tower.

4c. In a lift bridge, the combination with stationary towers, of a counterbalanced span adapted for vertical travel between said towers, a fixed lifting and lowering maohinery, flexible pulling means extending from said machinery over guidingmeans at the upper part ofthe adjacent tower and over guides in the span to a fixed point in the upper part of. the other tower, flexible pulling means extending from said machinery over guiding means at the lower part of the adjacent tower, over guides in the span'to a fixed pointin the lower part of the other tower, and Z-shaped flexible pulling means of which the one extends from a fixed point at the top of one tower over guides in the span to a fixed point at pulling means of which the one extends from 10 afixed point at the top of one tower over guides in the span to a fixed point at the foot of the other tower and the other extends from a fixed point at the top of the other tower over guides in the span to a fixed 15 point at the foot of the first mentioned tower. In testimony whereof I afiix my signature.

PIETER JOOSTING. 

